An Exterior model of the MK2 police box originally designed in the 1930's taken from authentic blue prints I found on a TARDIS web site years ago. This is the original police box, the BBC set designers made modifications to this design in making TARDIS props.
For a history of the police box and the evolution of the TARDIS design, I strongly suggest looking at The TARDIS Library site: http://homepages.paradise.net.nz/~trekker/policeboxes/realboxes.html